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    Fourtitude.com


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    1. Member im_n2_vws's Avatar
      Join Date
      Jul 25th, 2007
      Location
      Sardinia, Ohio
      Posts
      283
      Cars
      68 Beetle,69 Squareback,70 rail buggy,88 Jetta parts car,91 Jetta 1.6 na diesel,92 Jetta 8v
      03-03-2008 06:47 PM #1
      I have an 85 Jetta 1.6 na diesel. I need to know where the blue wire that goes to the battery indicator light in the dash goes under the hood? Mine has been cut very short up by one of the connections. Does it go to the alternator? I've been having some charging/ starting issues and was wondering if this might be a problem. Thanks,

      Danny

      68 Beetle,69 squareback
      70 "reconstructed" rail buggy
      88 Jetta GL 8v parts car
      91 Jetta carat 8v parts car
      92 Jetta GL 8v daily driver

    2. 03-03-2008 06:53 PM #2
      Yup, this is the alternator exciter wire, and without it connected your alternator will probably not charge properly if at all.

      There are several different alternators used so it's hard to tell you where it goes without a picture of your specific beast. Diesel alternators have 2 or 3 connectiions:

      1) a big red wire going to a big stud or connector ("B+")
      2) the small blue exciter wire going to a small connector ("D+")
      3 an optional small wire going to the tachometer and oil pressure warning system ("W")

      Your blue wire needs to go to the D+ terminal or connector on your alternator.

      Vince Waldon
      Edmonton Alberta Canada
      2001 silver TDI Jetta, .205s and Malone Stage 1.5
      2001 blue TDI Jetta, .216s, SB III, and Malone Stage 3. grrrr baby...very grrrrrrr ;-)

    3. Member im_n2_vws's Avatar
      Join Date
      Jul 25th, 2007
      Location
      Sardinia, Ohio
      Posts
      283
      Cars
      68 Beetle,69 Squareback,70 rail buggy,88 Jetta parts car,91 Jetta 1.6 na diesel,92 Jetta 8v
      03-03-2008 08:23 PM #3
      My alternator has a plug on it with three wires coming out of it , two big red ones and a little red and black one. The two big red ones go to the big terminal on my starter. And the little red and black one goes into the same little loom as the blue wire. Is that right? A PO has definatly messed with the wiring, could evan be a different year alternator. There is no wire on the W terminal witch I have heard is for a tach. Thanks,

      Danny

      68 Beetle,69 squareback
      70 "reconstructed" rail buggy
      88 Jetta GL 8v parts car
      91 Jetta carat 8v parts car
      92 Jetta GL 8v daily driver

    4. 03-03-2008 10:05 PM #4
      OK, so the plug has two big thick wires that goes to the starter, and a thin red/black wire ?

      If there are is only one thin wire in the plug then that's the exciter wire.... as you mentioned, the W is optional. Although your harness may be wired for it it sounds like your alternator is not.


      Modified by Vincent Waldon at 6:08 PM 3-3-2008

      Vince Waldon
      Edmonton Alberta Canada
      2001 silver TDI Jetta, .205s and Malone Stage 1.5
      2001 blue TDI Jetta, .216s, SB III, and Malone Stage 3. grrrr baby...very grrrrrrr ;-)

    5. Member im_n2_vws's Avatar
      Join Date
      Jul 25th, 2007
      Location
      Sardinia, Ohio
      Posts
      283
      Cars
      68 Beetle,69 Squareback,70 rail buggy,88 Jetta parts car,91 Jetta 1.6 na diesel,92 Jetta 8v
      03-03-2008 11:18 PM #5
      So you think there is no need to worry about the blue wire going to the battery light ? Just seems like with it not hooked up I wouldn't know if something is wrong with the charging system. The wire itself is hot (checked with test light, not hot to the touch)Thanks,

      Danny

      68 Beetle,69 squareback
      70 "reconstructed" rail buggy
      88 Jetta GL 8v parts car
      91 Jetta carat 8v parts car
      92 Jetta GL 8v daily driver

    6. 03-03-2008 11:37 PM #6
      Yeah, sorry, it's tough to be clear without pictures !

      The wire to the battery light on the dash is the exciter wire... current passes thru the dash light and excites the alternator field windings.

      So, with no wire from the alternator to the dash light, alternator will likely not start the charging cycle, and as you've said you won't have a warning light when the belt breaks etc.

      If your alternator only has one thin wire coming out of it then that's the exciter lead that should go to the dash light. Can't really count on the colors matching if you think the PO was messing with things.

      If you had two thin wires coming out of the alt one would be the exciter and one the W, but it doesn't sound like this is the case.

      Bottom line... the thick wires from the alt go to the battery connection at the starter, and if you only have one thin wire from the alt it is most likely the exciter wire and needs to go to the light on the dash. I say "most likely" since it is possible that the PO cut off the exciter and left the W wire.

      The exciter wire read 12V btw because that's the voltage that excites the alternator.

      Clear as mud ??!!


      Vince

      One last thought.... if the above is still unclear (highly possible !) then I really suggest posting a couple of pictures... we can photoshop 'em with arrows to show what goes where.

      Vince Waldon
      Edmonton Alberta Canada
      2001 silver TDI Jetta, .205s and Malone Stage 1.5
      2001 blue TDI Jetta, .216s, SB III, and Malone Stage 3. grrrr baby...very grrrrrrr ;-)

    7. Member im_n2_vws's Avatar
      Join Date
      Jul 25th, 2007
      Location
      Sardinia, Ohio
      Posts
      283
      Cars
      68 Beetle,69 Squareback,70 rail buggy,88 Jetta parts car,91 Jetta 1.6 na diesel,92 Jetta 8v
      03-04-2008 03:06 PM #7
      Vincent, Clear as water!!! That was the problem. The p.o. must have switched wires somewhere. I tried first just using a jumper wire to switch the blue wire (going to dash) and red/black wire(coming from alternator) and the battery light on the dash came on for a few seconds after starting then went out!!! I permently wired the blue (to dash) and red/black(from alternator) together and left the other wire dead. I knew something was wired wrong because when I had my 91 running, the battery light would come on for just a second or two or if you just revved it up a little it wold go out. I was afraid that I was being as clear as mud with my description, glad you understood me. Thanks a million !!!!!!

      Danny

      68 Beetle,69 squareback
      70 "reconstructed" rail buggy
      88 Jetta GL 8v parts car
      91 Jetta carat 8v parts car
      92 Jetta GL 8v daily driver

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